Coating Systems

ABSTRACT

The invention provides coating systems comprising a) a base layer, b) middle layer and c) top layer, whereby each of the layers a), b) and c) is based on mineral binder, filler, polymers from one or more ethylenically unsaturated monomers and optional further additives, and whereby the middle layer contains additionally light weight aggregates.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the national phase filing of international patentapplication No. PCT/EP2011/060806, filed 28 Jun. 2011, and claimspriority of United Arab Emirates application number 2010/724-P, filed 30Jun. 2010, the entireties of which applications are incorporated hereinby reference.

FIELD OF THE INVENTION

The invention relates to coating systems, particularly roofing systems,comprising three layers on the basis of mineral binders, fillers,polymers as well as processes for the preparation of such coatingsystems.

BACKGROUND OF THE INVENTION

In construction engineering it is very common to prepare coating systemscomprising a number of different layers in order to fulfill therequirements for heat and sound insulation as well as protection againstrain or snow. Due to the long-term use of buildings and the high costsfor their renovation it is of high importance that each constructionalunit of buildings satisfies high demands. This is particularly true forcoating systems exposed to extreme temperatures and water, such asroofing systems. Thus, the durability of coating systems is ofparticular interest.

Therefore a number of coating systems have been developed up to now.Five or more layered coating systems are very common. Such systemscomprise for instance a primer prepared from a dissolved bitumen,secondly a bitumen membrane or a synthetic membrane, thirdly insulationsboards, such as extruded polystyrene, fourthly geo textile fabric,mainly of polyester or polypropylene in form of woven, and finally agravel top layer. The preparation of such multilayered coating systemsis very labor-, cost- and time-intensive. Furthermore, many differentcomponents have to be applied resulting in a complex logistic at thebuilding site. Such or related systems are described for example in FR-A2554151, U.S. Pat. No. 4,272,936, KR 20040025261, CN 1417432, CN101413326, CN 201195921 or CN 1777893.

SUMMARY OF THE INVENTION

It was therefore an object to provide coating systems, particularlyroofing systems, which show high technical performance, such as a veryhigh durability and very good insulation properties, and which is basedon fewer or more similarly processable constituents, and which may beprepared in a more time and cost effective manner.

These and further objects were achieved with coating systems comprisinga) a base layer, b) a middle layer and c) a top layer, whereby each ofthe layers a), b) and c) is based on mineral binder, filler, polymersfrom one or more ethylenically unsaturated monomers and optional furtheradditives, and whereby the middle layer contains additionally lightweight aggregates.

DETAILED DESCRIPTION OF THE INVENTION

Light weight aggregate are generally known as low density aggregates,such as vermiculite, perlite, poraver glass beads, hollow glass spheres,natural lightweight aggregate, like pumice, expanded clays or shales,like ridgelite or utelite, sintered pulverised fuel ash.

Suitable polymers from ethylenically unsaturated monomers are forexample those based on one or more monomers from the group comprisingvinyl esters of carboxylic acids having from 1 to 15 carbon atoms,methacrylic esters or acrylic esters of carboxylic acids with unbranchedor branched alcohols having from 1 to 15 carbon atoms, olefins anddienes, vinylaromatics and vinyl halides.

Preferred vinyl esters are vinyl acetate, vinyl propionate, vinylbutyrate, vinyl-2-ethylhexanoate, vinyl laurate, 1-methylvinyl acetate,vinyl pivalate and vinyl esters of α-branched monocarboxylic acidshaving from 9 to 13 carbon atoms, for example VeoVa9R or VeoVa10R (tradenames of Shell). Particular preference is given to vinyl acetate.

Preferred methacrylic esters or acrylic esters are methyl acrylate,methyl methacrylate, ethyl acrylate, ethyl methacrylate, propylacrylate, propyl methacrylate, n-butyl acrylate, n-butyl methacrylate,2-ethylhexyl acrylate, norbornyl acrylate. Preference is given to methylacrylate, methyl methacrylate, n-butyl acrylate and 2-ethylhexylacrylate.

Preferred olefins and dienes are ethylene, propylene and 1,3-butadiene.Preferred vinylaromatics are styrene and vinyltoluene. A suitable vinylhalide is vinyl chloride.

If appropriate, from 0.05 to 20% by weight, preferably from 1 to 10% byweight, based on the total weight of the base polymer, of auxiliarymonomers can be copolymerized in. Examples of auxiliary monomers areethylenically unsaturated monocarboxylic and dicarboxylic acids,preferably acrylic acid, methacrylic acid, fumaric acid and maleic acid;ethylenically unsaturated carboxamides and carboxylic nitriles,preferably acrylamide and acrylonitrile; monoesters and diesters offumaric acid and maleic acid, e.g. the diethyl and diisopropyl esters,and also maleic anhydride, ethylenically unsaturated sulfonic acids ortheir salts, preferably vinylsulfonic acid,2-acrylamido-2-methylpropanesulfonic acid. Further examples areprecrosslinking comonomers such as multiply ethylenically unsaturatedcomonomers, for example divinyl adipate, diallyl maleate, allylmethacrylate or triallyl cyanurate, or postcrosslinking comonomers, forexample acrylamidoglycolic acid (AGA), methyl methylacrylamidoglycolate(MAGME), N-methylolacrylamide (NMA), N-methylolmethacrylamide (NMMA),N-methylol allyl carbamate, alkyl ethers such as isobutoxy ether or theester of N-methylolacrylamide, of N-methylolmethacrylamide and ofN-methylol allyl carbamate. Also suitable are epoxy-functionalcomonomers such as glycidyl methacrylate and glycidyl acrylate. Furtherexamples are silicon-functional comonomers such asacryloxypropyltri(alkoxy)silanes andmethacryloxypropyltri(alkoxy)silanes, vinyltrialkoxysilanes andvinylmethyldialkoxysilanes, in which, for example, methoxy, ethoxy andethoxypropylene glycol ether radicals can be present as alkoxy groups.Mention may also be made of monomers having hydroxy or CO groups, forexample hydroxyalkyl methacrylates and acrylates, e.g. hydroxyethyl,hydroxypropyl or hydroxybutyl acrylate or methacrylate and alsocompounds such as diacetoneacrylamide and acetylacetoxyethyl acrylate ormethacrylate. Further examples are vinyl ethers such as methyl, ethyl orisobutyl vinyl ether.

Examples of suitable homopolymers and copolymers are vinyl esterhomopolymers, copolymers of one or more vinyl esters with ethylene,copolymers of vinyl acetate with ethylene and one or more further vinylesters, copolymers of one or more vinyl esters with ethylene and acrylicesters, styrene-acrylic ester copolymers, styrene-1,3-butadienecopolymers.

copolymers of one or more vinyl halogenides with α-olefins, such asethylene or propylene, and/or vinyl esters, such as vinyl acetate,and/or (meth)acrylic esters of unbranched or branched alcohols havingfrom 1 to 15 carbon atoms, such as methyl(meth) acrylate, ethyl(meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl(meth)acrylate, or 2-ethylhexyl (meth) acrylate,

Preference is given to vinyl acetate homopolymers; copolymers of vinylacetate with from 1 to 40% by weight of ethylene; copolymers of vinylacetate with from 1 to 40% by weight of ethylene and from 1 to 50% byweight of one or more further comonomers from the group comprising vinylesters having from 1 to 12 carbon atoms in the carboxylic acid radical,e.g. vinyl propionate, vinyl laurate, vinyl esters of alpha-branchedcarboxylic acids having from 9 to 13 carbon atoms, e.g. VeoVa9R,VeoVa10R, VeoVa11R; copolymers of vinyl acetate, from 1 to 40% by weightof ethylene and preferably from 1 to 60% by weight of acrylic esters ofunbranched or branched alcohols having from 1 to 15 carbon atoms, inparticular n-butyl acrylate or 2-ethylhexyl acrylate; and copolymerscomprising from 30 to 75% by weight of vinyl acetate, from 1 to 30% byweight of vinyl laurate or vinyl esters of an alpha-branched carboxylicacid having from 9 to 11 carbon atoms, and also from 1 to 30% by weightof acrylic esters of unbranched or branched alcohols having from 1 to 15carbon atoms, in particular n-butyl acrylate or 2-ethylhexyl acrylate,which may additionally contain from 1 to 40% by weight of ethylene;copolymers comprising vinyl acetate, from 1 to 40% by weight of ethyleneand from 1 to 60% by weight of vinyl chloride; copolymers comprisingfrom 30 to 75% by weight of vinyl chloride, from 1 to 30% by weight ofvinyl laurate or vinyl esters of an alpha-branched carboxylic acidhaving from 9 to 11 carbon atoms, and also from 1 to 40% by weight ofethylene; where the polymers can additionally contain theabove-mentioned auxiliary monomers in the amounts indicated and thefigures in % by weight in each case add up to 100% by weight.

Preference is also given to (meth)acrylic ester polymers such ascopolymers of n-butyl acrylate or 2-ethylhexyl acrylate or copolymers ofmethyl methacrylate with n-butyl acrylate and/or 2-ethylhexyl acrylateand, if appropriate, ethylene; styrene-acrylic ester copolymerscomprising one or more monomers from the group consisting of methylacrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate,2-ethylhexyl acrylate; vinyl acetate-acrylic ester copolymers comprisingone or more monomers from the group consisting of methyl acrylate, ethylacrylate, propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate and,if appropriate, ethylene; styrene-1,3-butadiene copolymers; vinylhalogenide polymers such as copolymers of vinyl chloride and ethylene;where the polymers can additionally contain the abovementioned auxiliarymonomers in the amounts indicated and the figures in % by weight in eachcase add up to 100% by weight.

The monomers and the proportions by weight of the comonomers are chosenso that, in general, a glass transition temperature Tg of from −50° C.to +50° C., preferably from −30° C. to +40° C., results. The glasstransition temperature Tg of the polymers can be determined in a knownway by means of differential scanning calorimetry (DSC). The Tg can alsobe calculated approximately beforehand by means of the Fox equation.According to Fox T. G., Bull. Am. Physics Soc. 1, 3, page 123 (1956):1/Tg=x1/Tg1+x2/Tg2+ . . . +xn/Tgn, where xn is the mass fraction (% byweight/100) of the monomer n and Tgn is the glass transition temperaturein Kelvin of the homopolymer of the monomer n. Tg values forhomopolymers are given in Polymer Handbook 2nd Edition, J. Wiley & Sons,New York (1975).

The polymers are prepared in a manner known per se, preferably inaqueous medium, for usually by the emulsion polymerization process, asdescribed in DE-A 102006007282 for example. Use may be made either ofemulsifier-stabilized dispersions or of dispersions stabilized withprotective colloid. The dispersions contain preferably protectivecolloids in amounts of 1 to 20 weight percent, based on the total weightof the monomers. The protective colloids may be anionic or preferablynon-ionic or cationic or combinations of non-ionic and cationicprotective colloids. Preferred non-ionic protective colloids arepolyvinyl alcohols. Suitable cationic protective colloids are polymershaving a cationic charge. Such polymers are described, for example, inE. W. Flick, Water-Soluble Resins—an Industrial Guide, NoyesPublications, Park Ridge, N.J., 1991. To prepare polymers in form ofwater-redispersible polymer powders, the resultant polymers in form ofaqueous dispersions are dried, preferably after addition of dryingassistants, such as polyvinyl alcohol. The method of drying may be spraydrying, freeze drying, or coagulation of the dispersion followed byfluidized-bed drying. Spray drying is preferred. The polymers in form ofwater-redispersible powders contain protective colloids in amounts ofpreferably 3 to 30 weight percent, based on the total weight of thepolymer components.

The polymers are applied preferably in form of water-redispersiblepowders stabilized by one or more protective colloids.

The polymers from ethylenically unsaturated monomers may also be appliedin form of polymer compositions containing one or more polymers fromethylenically unsaturated monomers, preferably stabilized by one or moreprotective colloids, and one or more further additives, such ashydrophobicizing additives H). Examples of such hydrophobicizingadditives H) are additives H1), i.e. fatty acids or fatty acidderivatives and/or additives H2), i.e. organosilicon compounds. Ingeneral, additives H) are used in amounts of 1% to 20% by weight,preferably 1% to 10% by weight, based in each case on the total weightof the polymer composition.

Suitable for use as additives H1) are, generally, fatty acid compoundsfrom the group consisting of fatty acids having 8 to 22 carbon atoms,their metal soaps, their amides, and their esters with monohydricalcohols having 1 to 14 carbon atoms, with glycol, with polyglycol, withpolyalkylene glycol, with glycerol, with mono-, di- or triethanolamine,or with monosaccharides.

Examples for fatty acids are n-dodecanoic acid, n-tetradecanoic acid,n-hexadecanoic acid, n-octadecanoic acid and 9-dodecenoic acid. Suitablemetal soaps are those of the aforementioned fatty acids with metals frommain group lithium, sodium, potassium, magnesium, calcium, aluminium andzinc and with the ammonium compounds. Suitable fatty acid amides arethose obtainable with mono- or diethanolamine and with theabovementioned C₈ to C₂₂ fatty acids. Fatty acid esters are for examplethe C₁ to C₁₄ alkyl and alkylaryl esters of the stated C₈ to C₂₂ fattyacids, preferably methyl, ethyl, propyl, butyl and ethylhexyl esters andalso the benzyl esters. Suitable fatty acid esters are also the mono-,di- and polyglycol esters of the C₈ to C₂₂ fatty acids. Further suitablefatty acid esters are the monoesters and diesters of polyglycols and/orpolyalkylene glycols having up to 20 oxyalkylene units, such aspolyethylene glycol and polypropylene glycol. Also suitable are themono-, di- and tri-fatty acid esters of glycerol with the stated C₈ toC₂₂ fatty acids, and also the mono-, di- and tri-fatty acid esters ofmono-, di- and triethanolamine with the stated C₈ to C₂₂ fatty acids.Also suitable are the fatty acid esters of sorbitol and mannitol.

Particularly preferred are the C₁ to C₁₄ alkyl and alkylaryl esters oflauric acid and oleic acid, mono- and diglycol esters of lauric acid andoleic acid, and the mono-, di- and tri-fatty acid esters of glycerolwith lauric acid and oleic acid.

Suitable additives H2) are silicic esters Si(OR′)₄, silanes such astetraorganosilanes SiR₄ and organoorganoxysilanes SiR_(n)(OR′)_(4-n)with n=1 to 3, polysilanes with preferably the general formulaR₃Si(SiR₂)_(n)SiR₃ with n=0 to 500, organosilanols SiR_(n)(OH)_(4-n),di-, oligo- and polysiloxanes composed of units of the general formulaR_(c)H_(D)Si(OR′)_(e)(OH)_(f)O_((4-c-d-e-f)/2) with c=0 to 3, d=0 to 1,e=0 to 3, f=0 to 3 and the sum c+d+e+f not more than 3.5 per unit, R ineach case being identical or different and denoting branched orunbranched alkyl radicals having 1 to 22 carbon atoms, cycloalkylradicals having 3 to 10 carbon atoms, alkylene radicals having 2 to 4carbon atoms, and aryl, aralkyl and alkylaryl radicals having 6 to 18carbon atoms, and R′ denoting identical or different alkyl radicals andalkoxyalkylene radicals having in each case 1 to 4 carbon atoms,preferably methyl and ethyl, it also being possible for the radicals Rand R′ to be substituted by halogens such as Cl or by ether, thioether,ester, amide, nitrile, hydroxyl, amine, carboxyl, sulphonic acid,carboxylic anhydride and carbonyl groups, and in the case of thepolysilanes it also being possible for R to have the definition OR′.Also suitable are carbosilanes, polycarbosilanes, carbosiloxanes,polycarbosiloxanes and polysilylenedisiloxanes.

Preferred additives H2) are tetramethoxysilane, tetraethoxysilane,methyltripropoxysilane, methyltri(ethoxyethoxy)silane,vinyltri(methoxyethoxy)silane, (meth)acryloyloxypropyltrimethoxysilane,(meth)acryloyloxypropyltriethoxysilane, γ-chloropropyltriethoxysilane,β-nitriloethyltriethoxysilane, γ-mercaptopropyltrimethoxysilane,γ-mercaptopropyltriethoxysilane, phenyltriethoxysilane,isooctyltriethoxysilane, n-octyltriethoxysilane,hexadecyltriethoxysilane, dipropyldiethoxysilane,methylphenyldiethoxysilane, diphenyldimethoxysilane,methylvinyltri(ethoxyethoxy)silane, tetramethyldiethoxydisilane,trimethyltrimethoxydisilane, trimethyltriethoxydisilane,dimethyltetramethoxydisilane, dimethyltetraethoxydisilane,methylhydropolysiloxanes terminally blocked with trimethylsiloxy groups,copolymers of dimethylsiloxane and methylhydrosiloxane units that areterminally blocked with trimethylsiloxy groups, dimethylpolysiloxanes,and also dimethylpolysiloxanes having Si—OH groups in the terminalunits. Maximum preference is given to the organoorganoxysilanesSiR_(n)(OR′)_(4-n) with n=1 to 3, especially isooctyltriethoxysilane,n-octyltriethoxysilane and hexadecyltriethoxysilane.

The polymer composition may be present in form of aqueous dispersions orpreferably in form of water-redispersible powders. The preparation ofthe polymer compositions is known in the art and described for examplein EP-A 1763553.

Suitable mineral binders are for example cement, such as Portland cementor blast funast cement, aluminate cement, silica dust cement, gypsum,waterglass or lime hydrate. Preferred is Portland cement, optionally incombination with aluminate cement.

Examples of fillers which can be used are carbonates such as calciumcarbonate in the form of dolomite, calcite and chalk. Further examplesare silicates, such as magnesium silicate in the form of talc, oraluminium silicates such as loam and clays; quartz flour, quartz sand,highly disperse silica, feldspar, heavy spar and light spar, fillershaving a pozzolanic reaction, such as fly ash, metakaolin, microsilicaor rubber shreds. Also suitable are fibrous fillers. In practice,mixtures of different fillers are frequently used. Generally less than10%, preferably less than 5% by weight gravel is applied, based on thetotal amount of filler. More preferably no gravel is applied.

The fillers have preferably average diameters of from 0.01 to 4 mm,particularly preferably from 0.05 to 0.5 mm.

Examples of further additives are pigments, an example being titaniumdioxide as an inorganic pigment, and also the customary organicpigments. Examples of further additives are wetting agents in fractionsof generally 0.1% to 0.5% by weight, based on the total weight of therespective formulation. Examples of such are sodium or potassiumpolyphosphates, polyacrylic acids and salts thereof. Other additiveswhich may be mentioned include thickeners, which are generally used inan amount of 0.01% to 2.0% by weight, based on the total weight of therespective formulation. Customary thickeners are cellulose ethers,starches, phyllosilicates, or bentonite, as an example of an inorganicthickener.

Further additives are preservatives, defoamers, air-pore formers,plasticizers, retardants, accelerants and frost preventatives.

A typical formulation for the preparation of the base layer a) contains5% to 25% by weight, preferably 8% to 20% by weight of one or moremineral binders, 10% to 30% by weight, preferably 10% to 25% by weightof one or more polymers, and 50% to 85% by weight, preferably 60% to 80%by weight of one or more fillers, and optionally 0.01% to 5% by weight,preferably 0,1% to 2% by weight of one or more additives, the amounts in% by weight in the formulation adding up to 100% by weight.Additionally, 20% to 40% by weight of water is used, based on the totalweight of the formulation.

Polymers containing units of one or more vinyl esters and ethylene arepreferred for the base layer a). The polymers applied for thepreparation of the base layer a) have a glass transition temperature Tgof preferably from −20° C. to +20° C. The amount of the polymers as wellas the glass transition temperature Tg contributes to the flexibility ofthe base layer a) and works against the occurrence of cracks in thecoating systems.

A typical formulation for the preparation of the middle layer b)contains 30% to 70% by weight, preferably 40% to 60% by weight of one ormore mineral binders, 0.1% to 10% by weight, preferably 0.5% to 5% byweight of one or more polymers, and 10% to 50% by weight, preferably 20%to 40% by weight of one or more light weight aggregates, 10% to 30% byweight, preferably 15% to 25% by weight of one or more fillers otherthan light weight aggregate, 0% to 5% by weight, preferably 0.1% to 2%by weight of one or more additives, preferably plasticizers orretardants, the amounts in % by weight in the formulation adding up to100% by weight. Additionally, 20% to 30% by weight of water is used,based on the total weight of the formulation.

The middle layer b) contains as light weight aggregate preferablyvermiculite, perlite, poraver glass beads, hollow glass spheres, naturallightweight aggregate, like pumice, expanded clays or shales, likeridgelite or utelite, sintered pulverised fuel ash or various blendsthereof. More preferred light weight aggregate are perlite, poraverglass beads or vermiculite. The light weight aggregates have preferablyan average diameter of from 1 to 4 mm, particularly preferably from 2 to4 mm.

The middle layer b) contains preferably superfine filler, such as microsilica, silica flour, calcium carbonate, preferably in combination withthe above mentioned fillers. The amount of superfine filler ispreferably 1% to 5% by weight, more preferably 1.5% to 4% by weight,based on the total amount of fillers. The application of superfinefiller reduces the number of pores or pore volume of the coating systemand improves the density of the coating system.

The mineral binder applied for the middle layer b) is preferably acombination of an aluminate cement and one or more further mineralbinders. The ratio of aluminate cement to cement is preferably 1 to 3till 3 to 1. These measures accelerate the manufacturing speed of thecoating system.

Polymers containing units of one or more vinyl esters and ethylene arepreferred for the middle layer b).

A typical formulation for the preparation of the top layer c) contains35% to 50% by weight, preferably 40% to 50% by weight of one or moremineral binders, 1% to 5% by weight, preferably 1% to 5% by weight ofone or more polymers and/or one or more polymer compositions containingone or more hydrophobicizing additives H), and 40% to 60% by weight,preferably 45% to 55% by weight of filler, 0% to 5% by weight,preferably 0.05% to 2% by weight of one or more additives, such asthickeners or pigments, the amounts in % by weight in the formulationadding up to 100% by weight. Additionally, 20% to 40% by weight,preferably 20% to 30% by weight of water is used, based on the totalweight of the formulation.

Polymers containing units of vinyl chloride, one or more vinyl esters,such as vinyl acetate and/or vinyl laurate, and ethylene are preferredfor the top layer c).

Coating agents a), b) or c) are prepared from the constituents of therespective formulation for the base layer a), the middle layer b) or thetop layer c). The preparation of the coating agents is not associatedwith any specific measure and can be performed with well-knownequipment. Preferably, the dry components of each formulation are mixedfirst and water as well as liquid components are added subsequently.

Appropriate undergrounds for the base layer a) are cement bondedundergrounds, such as concrete or screeds, rocks or boulders, forinstance.

Each of the coating agents a), b) and c) might be applied by manualmethods or mechanical methods, such as spraying machines. The coatingagents are for usually applied at temperatures common in theconstruction sector, such as at temperatures from 0 to 50° C. For thepreparation of the coating system the underground is coated with one ormore layers of coating agent a), upon which one or more layers ofcoating agent b) are applied, upon which one or more layers of coatingagent c) are applied. The middle layer b) is applied preferably directlyonto the base layer a). The top layer c) is applied preferably directlyonto the middle layer b). In general, the coating agents a), b) and c)have set before another coating agent is applied onto it.

Alternatively the underground might be coated with one or more primers,before the application of the coating agent a). Alternatively, but lesspreferred there might be applied a further coating between the layer a)and b) or between the middle layer b) and the top layer c). Furthermore,top layer c) might be coated with a finishing, such as tile.

In general, the coating agent b) is applied 0.5 to 10 days, morepreferably 1 to 5 after the application of the coating agent a). Thecoating agent c) is generally applied 0.5 to 10 days, more preferably 1to 5 after the application of the coating agent b). The whole coatingsystem has set preferably 10 days, more preferably 7 days after theapplication of the base coating a).

The thickness of the base layer a) is preferably 0.1 to 1 cm, morepreferably 0.2 to 0.4 cm. The thickness of the middle layer b) ispreferably 1 to 5 cm, more preferably 2 to 3 cm. The thickness of thetop layer c) is preferably 0.1 to 1 cm, more preferably 0.2 to 0.4 cm.The thickness of the entire coating systems is preferably 2 to 7 cm,more preferably 2 to 4 cm.

The most preferred application of the coating systems is for roofingsystems.

Advantageously, the preparation of the instant coating system is veryeffective with respect to the production time as well as the logisticefforts at the building site. The raw materials exist in a uniform formand may be furnished to the construction site as a ready to use premixsuch that for each of the coating layers only one coating agent needs tobe handled and the coating agents for the different layers may beapplied in the same way, for example with the same machines.Furthermore, the instant coating system shows excellent technicalperformance, such as high water proofness, flexibility with respect tomechanical strain, solar irradiation, thermal insulation against heat orcold as well as sound dampening.

But the most important aspect of the instant invention is thesynergistic effect of the different layers a), b) and c) which resultsin a surprisingly high durability of the system, e.g. a very highresistance against demands typical for coating systems, particularlyroofing systems, such as for example heat, cold, water and frost, solarirradiation or corrosive air. This prolongs the lifetime of the coatingsystem as well as the entire building and reduces the need forrestoration which is very cost intensive.

The examples which follow serve to illustrate the invention further.

The coating agent a) was prepared by mixing the following components asdescribed in EN 14891:2006:

Sand (0-0.3 mm) 55% per weight, Grey Cement 12% per weight, CalciumCarbonate (filler) 10% per weight, Foamaster (anti-foaming agent) 0.2%per weight, Bentonil CF (filler) 1.5% per weight, Micro Silica 0.55% perweight, Arbocel BC 1000 (additive) 0.75% per weight, Vinnapas 5044N* 20%per weight, and 50% by water, based on the total weight of the drycomponents of the recipe. *: Polyvinyl alcohol stabilized vinylacetate-ethylene copolymer in the form of a water-redispersible powder;

Coating agent a) was applied with a straight edge trowel on a concretesubstrate to give the base layer a) having a thickness of 0.3 cm. Afterstorage for 28 days under standard conditions as defined in EN14891:2006 the base layer a) was tested as per EN 14891:2006. Theresults are summarized in Table 1.

TABLE 1 Test results obtained with the base layer a): Tests according toEN14891:2006: Base layer a) Tensile Adhesion [N/mm²] 1.74 HydrostaticPressure Withstand 1.5 bars for 7 days Crack bridging ability [mm] 0.60

The coating agent b) was prepared by mixing the following components asdescribed in EN 196-1:2004:

Portland Cement CEM 42.5 10.9 per weight, Cement Fondu (HAC) 21.8 perweight, Hydrated Lime (a mineral binder) 0.87 per weight, Citric Acid(additive) 0.35 per weight, Anhydrate-selecta (a mineral binder) 11.63per weight, Super plasticiser—Melflux PP 100F 0.28 per weight, Silicasand (0-300 mic) 17.24 per weight, VINNAPAS 5044 N* 2.0 per weight,Perlite (1-4 mm) 32.5 per weight, Micro Silica 2.43 per weight, and 25%-by water, based on the total weight of the dry components of the recipe.*: Polyvinyl alcoholstabilized vinyl acetate-ethylene copolymer in theform of a water-redispersible powder;

Coating agent b) was applied with a straight edge trowel on a concretesubstrate to give the middle layer b) having a thickness of 2.5 cm. Themiddle layer b) was tested as per EN13813:2005 after storage for a timespecified in Table 2 under standard conditions according to EN13813:2005. The results are summarized in Table 2.

TABLE 2 Test results obtained with the middle layer b): Middle layer b)[N/mm²] Compressive Strength after 7 days 12.67 Compressive Strengthafter 28 days 16.06 Compressive Strength after 28 days 3.37 FlexuralStrength after 7 days 2.22

The coating agent c) was prepared by mixing the following components asdescribed in EN 196-1: 2004:

White Cement 45 per weight, Sand (0-0.6 mm) 51.5 per weight, Walocel MKX6000 PF01 0.2 per weight, (methyl cellulose; thickener) Vinnapas 8034 H*3 per weight, Bentonil CF (filler) 0.3 per weight, and 25% by water,based on the total weight of the dry components of the recipe. *:Polyvinyl alcohol stabilized polymer composition in the form of awater-redispersible powder containing calcium stearate and a terpolymerfrom vinyl chloride, vinyl acetate and ethylene;

Coating agent c) was applied with a straight edge trowel on a concretesubstrate to give the top layer c) having a thickness of 0.3 cm. Afterstorage for 28 days under standard conditions as defined in EN 14891 thetop layer c) tested as per EN 14891. The results are summarized in Table3.

TABLE 3 Test results obtained with the top layer c): Top layer c)Compressive Strength [N/mm²] 33.5 Flexural Strength [N/mm²] 8.7Shrinkage [mm/m] 1.71 Water Impermeability—EN 14891 Withstand 1.5 barfor 7 days

A coating system was constructed by performing the following steps inthe following order:

-   -   the coating agent a) from the above described experiment was        applied with a straight edge trowel on a concrete substrate to        give a layer having a thickness of 0.3 cm;    -   storage of the thus obtained layer for 3 days under standard        conditions as defined in EN 14891:2006 gave the base layer a);    -   the coating agent b) from the above described experiment was        applied with a straight edge trowel on the aforementioned base        layer a);    -   the thus obtained coating system was stored for 3 days under        standard conditions as defined in EN 14891:2006; afterwards, the        coating system based on coating agents a) and b) had a thickness        of 2.8 cm;    -   the coating agent c) from the above described experiment was        applied with a straight edge trowel on the aforementioned        coating system based on coating agents a) and b);    -   the thus obtained coating system was stored for 1 day under        standard conditions as defined in EN 14891:2006; afterwards, the        entire coating system, e.g. the coating system based on coating        agents a), b) and c) had a thickness of 3.1 cm.

The entire coating system was tested against the following twostandards:

-   -   1) The thermal conductivity as per ASTM C 518 and the results        were in average 0.2 W/m.K. The specimen was conditioned in such        a way that change in mass within 24 hours was less than 1%. The        conditioning of the specimen was carried out in accordance to        ASTM C 518-02. Caluse 7.3.    -   2) The sound insulation test as per ASTM E-90: 2004. The        improved STC by using the system was by 4 dB.

1. Coating systems comprising a) a base layer, b) a middle layer and c)a top layer, whereby each of the layers a), b) and c) is based onmineral binder, filler, polymers from one or more ethylenicallyunsaturated monomers and optional further additives, and whereby themiddle layer contains additionally light weight aggregates.
 2. Coatingsystems according to claim 1, characterized in that one or more lightweight aggregates are selected from the group comprising vermiculite,perlite, poraver glass beads, hollow glass spheres, natural lightweightaggregate, expanded clays, shales and sintered pulverised fuel ash. 3.Coating systems according to claim 1 or 2, characterized in that thepolymers are applied in form of polymer compositions containing one ormore polymers from ethylenically unsaturated monomers and one or morehydrophobicizing additives H) from the group comprising H1) fatty acidsor fatty acid derivatives and H2) organosilicon compounds.
 4. Coatingsystems according to claims 1 to 3, characterized in that the polymersfrom ethylenically unsaturated monomers are based on one or moremonomers from the group comprising vinyl esters of carboxylic acidshaving from 1 to 15 carbon atoms, methacrylic esters or acrylic estersof carboxylic acids with unbranched or branched alcohols having from 1to 15 carbon atoms, olefins and dienes, vinylaromatics and vinylhalides.
 5. Coating systems according to claims 1 to 4, characterized inthat the fillers have average diameters of from 0.01 to 4 mm.
 6. Coatingsystems according to claims 1 to 5, characterized in that theformulation for the preparation of the base layer a) contains 5% to 25%by weight of one or more mineral binders, 10% to 30% by weight of one ormore polymers, and 50% to 85% by weight of one or more fillers, andoptionally 0.01% to 5% by weight of one or more additives, the amountsin % by weight in the formulation adding up to 100% by weight. 7.Coating systems according to claims 1 to 6, characterized in that theformulation for the preparation of the middle layer b) contains 30% to70% by weight of one or more mineral binders, 0.1% to 10% by weight ofone or more polymers, and 10% to 50% by weight of one or more lightweight aggregates, 10% to 30% by weight of one or more fillers otherthan light weight aggregate, and optionally 0% to 5% one or moreadditives, the amounts in % by weight in the formulation adding up to100% by weight.
 8. Coating systems according to claims 1 to 7,characterized in that the formulation for the preparation of the middlelayer b) contains additionally one or more superfine fillers selectedfrom the group comprising micro silica, silica flour and calciumcarbonate.
 9. Coating systems according to claims 1 to 8, characterizedin that the formulation for the preparation of the top layer c) contains35% to 50% by weight of one or more mineral binders, 1% to 5% by weightof one or more polymers and/or polymer compositions containing one ormore hydrophobicizing additives H), and 40% to 60% by weight of one ormore fillers, and optionally 0% to 5% by weight of one or moreadditives, the amounts in % by weight in the formulation adding up to100% by weight.
 10. Coating systems according to claims 1 to 9,characterized in that at least one polymer of the top layer c) containsone or more monomer units selected from the group comprising vinylchloride, vinyl ester and ethylene.
 11. Coating systems according toclaims 1 to 10, characterized in that the thickness of the base layer a)is 0.1 to 1 cm, the thickness of the middle layer b) is 1 to 5 cm, thethickness of the top layer c) is 0.1 to 1 cm.
 12. Coating systemsaccording to claims 1 to 11, characterized in that the coating systemsare roofing systems.
 13. Processes for the preparation of the coatingsystems according to claims 1 to 12, characterized in that anunderground is coated with one or more layers of coating agent a), uponwhich one or more layers of coating agent b) are applied, upon which oneor more layers of coating agent c) are applied.